package com.atguigu.crowd.mvc.config;

import com.autguigu.crowd.constant.CrowdConstant;
import com.autguigu.crowd.exception.AccessForbiddenException;
import com.autguigu.crowd.exception.LoginAccountAlreadyInUseException;
import com.autguigu.crowd.exception.LoginAccountAlreadyInUseForUpdateException;
import com.autguigu.crowd.exception.LoginFailedException;
import com.autguigu.crowd.util.CrowdUtil;
import com.autguigu.crowd.util.ResultEntity;
import com.google.gson.Gson;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 尚筹网项目异常处理类
 *
 * @author wmb
 *
 * @since 2021-1-17
 */
@ControllerAdvice   // @ControllerAdvice表示当前类是一个基于注解的异常处理器类
public class CrowdExceptionResolver {

    @ExceptionHandler(value = LoginAccountAlreadyInUseForUpdateException.class)
    public ModelAndView resolveLoginAccountAlreadyInUseForUpdateException(LoginAccountAlreadyInUseForUpdateException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        String viewName = "system-error";
        return commonResolver(viewName, exception, request, response);
    }

    @ExceptionHandler(value = LoginAccountAlreadyInUseException.class)
    public ModelAndView resolveLoginAccountAlreadyInUseException(LoginAccountAlreadyInUseException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        String viewName = "admin-add";
        return commonResolver(viewName, exception, request, response);
    }

    @ExceptionHandler(value = AccessForbiddenException.class)
    public ModelAndView resolveAccessForbiddenException(AccessForbiddenException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        String viewName = "admin-login";
        return commonResolver(viewName, exception, request, response);
    }

    @ExceptionHandler(value = LoginFailedException.class)
    public ModelAndView resolveLoginFailedException(LoginFailedException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        String viewName = "admin-login";
        return commonResolver(viewName, exception, request, response);
    }


    @ExceptionHandler(value = ArithmeticException.class)
    public ModelAndView resolveArithmeticException(ArithmeticException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        return commonResolver("system-error", exception,  request, response);
    }

    // @ExceptionHandler将一个具体的异常类型和一个方法关联起来
    @ExceptionHandler(value = NullPointerException.class)
    public ModelAndView resolveNullPointerException(NullPointerException exception, HttpServletRequest request, HttpServletResponse response) throws IOException {
        return commonResolver("system-error", exception,  request, response);
    }

    private ModelAndView commonResolver(
                            // 异常处理完成后要去的页面
                            String viewName,
                            // 实际捕获到的异常类型
                            Exception exception,
                            // 当前请求对象
                            HttpServletRequest request,
                            // 当前相应对象
                            HttpServletResponse response) throws IOException {
        // 1.判断当前请求类型
        boolean judgeResult = CrowdUtil.judgeRequestType(request);

        // 2.如果是Ajax请求
        if (judgeResult) {
            // 3.创建ResultEntity对象
            ResultEntity<Object> resultEntity = ResultEntity.failed(exception.getMessage());

            // 4.创建Gson对象
            Gson gson = new Gson();

            // 5.将ResultEntity对象转换为JSON字符串
            String json = gson.toJson(resultEntity);

            // 6.将JSON字符串作为响应体返回给浏览器
            response.getWriter().write(json);

            // 7.由于上面已经通过原生的response对象返回了响应，所以不提供ModelAndView对象
            return null;
        }

        // 8.如果不是Ajax请求则创建ModelAndView对象
        ModelAndView model = new ModelAndView();

        // 9.将Exception对象存入模型
        model.addObject(CrowdConstant.ATTR_NAME_EXCEPTION, exception);

        // 10.设置对应的视图名称
        model.setViewName(viewName);

        // 11.返回ModelAndView对象
        return model;
    }
}
